Violetta A. Murashova

Influence of the internal structure of a capillary channel on the propagation of soft x radiation

In the last years several coherent phenomena associated with the propagation of soft x-ray synchrotron radiation through capillary optical elements (polycapillary lenses and systems of capillaries) have been observed and investigated. Interference effects produced by soft x radiation travelling inside assembled capillary systems may be explained in the framework of the wave propagation theory. In this report a theoretical analysis of the dependence of the transmission characteristics by the internal structure of the capillary channel is presented and discussed.

Optical luminescence of solids under focusing of soft x rays by capillary systems

The capillary focusing system has been installed into the entrance arm of the station for time-resolved studying otpical luminescence of solid state materials under soft x- ray excitation. A sensitivity of the installation as well as a spectral resolution of the analyzing monochromator can be strongly enlarged by means of the lens giving a small spot of radiation on the sample with considerably higher photon flux compared with a direct synchrotron radiation beam.

Synchrotron radiation focusing by means of Kumakhov lenses

Results of experiments on focusing of synchrotron radiation by means of Kumakhov lens are presented. For explanation of observed interference structure the wave theory describing channeling radiation is applied.

Passage of synchrotron radiation through capillary macrosystems

The results of experimental and theoretical studies on passage of synchrotron radiation through capillary lenses of new generation are presented. The transmission coefficients for these systems in the range 8 - 10 angstrom are measured. An explanation of structure absence for focal spot is given.

CVD diamond films for synchrotron radiation beam monitoring

Free-standing polycrystalline diamond films grown by microwave plasma CVD technique were tested for detection X- ray radiation from a synchrotron source. Two different configurations of collection electrodes on diamond were used. The first (sandwich) geometry uses a thin amorphous conducting layers formed by nitrogen ion irradiation on both sides of the diamond plate. The second (planar) one, which showed better characteristics, comprises of an interdigitated planar array of metallic contacts on a face exposed to photon flux. However, in both cases a polarization effect that leads to a decrease of the detector response with exposition time, was observed. Better device performance is expected for diamond films of improved quality.

Enhancement of optical luminescence of solids using a capillary lens

A capillary focusing system has been installed to the experimental station of the SR source at the S-60 LPI (Moscow) dedicated to time-resolved optical luminescence of solid state materials excited by soft X-ray radiation of about 1 keV. We have demonstrated that the sensitivity of the detector as well as the spectral resolution of the analyzing monochromator have been strongly enhanced by capillary lens focusing the soft X-ray radiation in a tiny spot to the sample with a considerable enhancement of the photon flux compared with the unfocused synchrotron radiation beam.

Capillary optics: experimental study by the S-60

In this report the main results of experimental study on possibility to apply capillary structures for handling soft synchrotron radiation are presented. This research has been done at the S-60 FIAN accelerator facilites for the period 1993-1999. The possibility of using capillary systems to control the parameters of soft SR, such as radiation density and bending of beam, at the specified wavelength range has been experimentally confirmed. Discovered for the first time the structural radiation redistribution at the focal plane behind the capillary halflenses was carefully studied in experiments with two bent capillaries of focusing geometry. As a result the wave scattering theory of radiation inside the capillary channels was developed. The first experiments on measuring the luminescence spectrum for Ce3+ lithium/yttrium fluoride matrix by the use of capillary halflens has been done in comparison with the spectrum for the direct SR beam. The last confirms the fact that capillary optics is useful instruments to condense the radiaton beam on the samples of small sizes.

Bending of a synchrotron radiation beam by means of capillary systems

The results on bending of synchrotron radiation beam over large angles by means of capillary structures are presented. A possibility of beam bending not only on plane of electron orbit, but also a possibility of x-ray beam leading out a horizontal plane of the accelerator is shown. In the report a problem of synchrotron radiation polarization is discussed. A comparative analysis of the result of computer simulations and experiments is given.